Temperature-controlled concrete countertop

ABSTRACT

A concrete countertop includes a concrete slab that defines a substantially planar work surface. The work surface is treated for direct contact with foodstuffs. A piping circuit is embedded within the concrete slab and is coupled to a refrigeration motor for circulating refrigerant through the piping circuit. The concrete slab and work surface are thereby cooled by the circulation of refrigerant through the piping circuit. In another aspect, the concrete countertop may additionally, or alternatively, include a heating element embedded within the concrete slab to facilitate maintaining the work surface at an elevated temperature. The concrete countertop may further include a control communicating with the refrigeration motor and/or the heating element and operative to maintain the work surface within a desired temperature range.

FIELD OF THE INVENTION

The present invention relates generally to countertop structures, and more particularly to a temperature controlled concrete countertop.

BACKGROUND OF THE INVENTION

Concrete has long been used as a structural building material for forming building elements such as walls and floors. Recently, concrete has been used to form countertop surfaces, providing an alternative to other surface materials, which may be natural materials, such as granite or marble, or resinous man-made materials, such as Corian®. In certain applications, it may be desirable to prepare foodstuffs on a countertop surface. When foodstuffs will be in direct contact with the countertop surface, the surface must be prepared such that it is suitable for contact with the food.

In the preparation of certain foodstuffs such as pastries, chocolates, or other confectionary items, it is desirable to maintain the foodstuff at a reduced temperature so that the foodstuff may be more easily prepared and handled. For example, chocolate confections that are prepared at reduced temperatures more readily hold a set shape, thereby facilitating the formation of decorative designs as may be desired. In other applications, it may be desirable to maintain foodstuffs at elevated temperatures during preparation.

Various devices have been proposed for cooling a surface for the display of foods. These prior devices have generally located cooling components beneath a surface, such as a marble block, or sandwiched the cooling components between two different materials. The cooling characteristics of these devices are less than desirable, due to the different thermal properties of the different materials used in their construction. Moreover, none of these devices are configured to permit the preparation of foodstuffs directly on a concrete surface that is suitable for use as a countertop in residential or commercial kitchens.

A need therefore exists for a device that facilitates preparing foodstuffs under controlled temperature conditions and overcomes drawbacks of the prior art, such has those discussed above.

SUMMARY OF THE INVENTION

The present invention provides a concrete countertop with a work surface that is suitable for direct contact with foodstuffs and which can be controlled to maintain a desired temperature. In one embodiment, the countertop includes a concrete slab that has an embedded piping circuit. Refrigerant disposed within the piping circuit is circulated though the piping circuit by a refrigeration motor coupled to ends of the piping circuit. Accordingly, the concrete slab and work surface are cooled by the circulation of refrigerant through the piping circuit.

The concrete slab may be supported on a base, which may be in the form of a cabinet with wheels to facilitate moving the countertop, or in the form of a portable enclosure that can be placed on an existing counter structure. The concrete slab may be formed in any desired size or configuration needed. For example, a 24-inch square slab may be suitable for a portable concrete countertop. Larger slab sizes, such as 36-inches by 72-inches, or even larger, may be desired for more permanent countertop structures such as those built into commercial or residential kitchens.

In one aspect of the invention, the work surface has a highly polished finish obtained by polishing the concrete slab with a finishing tool of at least 3500 grit size. The work surface of the concrete slab is treated for direct contact with foodstuffs by a penetrating primer and a sealant applied to the work surface. The primer and sealant are safe for direct contact with food.

In another aspect of the invention, the concrete countertop includes a control for maintaining the work surface within the desired temperature range. The control may include a display, which could indicate a current or desired temperature of the work surface, and an input device to permit users to set a desired temperature of the work surface. The countertop may additionally, or alternatively, include a heating element embedded within the concrete slab to facilitate maintaining the work surface at an elevated temperature.

The features of the present invention will become more readily apparent from the following Detailed Description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with a general description of the invention given above, and the detailed description given below, serve to explain the invention.

FIG. 1 is a cross-sectional view depicting one embodiment of a countertop according to the present invention;

FIG. 2 is a cross-sectional view depicting another embodiment of a countertop according to the present invention; and

FIGS. 3-5 are perspective views depicting a method for creating a concrete countertop according to the present invention.

DETAILED DESCRIPTION

FIG. 1 depicts an exemplary concrete countertop 10 of the present invention, in cross-section. The countertop 10 includes a concrete slab 12 which has been treated and finished such that a work surface 14 of the slab 12 is suitable for direct contact with foodstuffs so that foodstuffs may be safely prepared directly thereon. Embedded within the concrete slab 12 is a piping circuit 16, which may be a continuous length of conduit 18 having first and second ends 20, 22. The conduit 18 may be shaped and arranged to facilitate cooling the concrete slab 12 and the work surface 14. For example, the conduit 18 may be bent to have a series of alternating turns at the ends of spaced, parallel straight sections of conduit, as best depicted in FIG. 3. It will be recognized that the conduit may be formed in various other manners, as desired, to create a passage through which a refrigerant may be circulated to facilitate cooling the concrete slab 10.

In the embodiment shown, an optional metal plate 19 is coupled to the piping circuit 16 to facilitate heat transfer between the piping circuit 16 and the concrete slab 12. The plate 19 may simply be in contact with the piping circuit 16, or it may be connected thereto, such as by welding, brazing, using mechanical fasteners, or by other methods. In this embodiment, the plate 19 is contiguous with the expanse of the piping circuit 16 in the concrete slab, and thereby covers an area that extends at least to the distal edges of the piping circuit 16. It will be recognized, however, that the plate 19 may alternatively cover and area that is greater or smaller than the area covered by the piping circuit 16.

With continued reference to the drawings, the first and second ends 20, 22 of conduit 18 are coupled, respectively, to inlet and outlet ports 24, 26 of a refrigeration motor 28 by fittings 25, such as quick-disconnect fittings, for example. The refrigeration motor 28 is coupled to an exterior power source 27 by a power cord 31 extending therefrom. In one embodiment, the exterior power source 27 may be a conventional 110 volt or 220 volt outlet. The refrigeration motor 28 will generally include a compressor and a refrigerant expansion device (not shown) whereby refrigerant that is contained within the piping circuit 16 may be circulated through the piping circuit 16 by the refrigeration motor 28 to thereby cool the concrete slab 12 and the work surface 14 of the countertop 10. Advantageously, the cooled work surface 14 facilitates the preparation of various foodstuffs directly thereon while maintaining the foodstuff at a reduced temperature.

The countertop 10 may further include a base or housing structure 30 to support the concrete slab 12. Advantageously, the base 30 may support the concrete slab 12 a distance above a floor surface so that the work surface 14 is conveniently positioned for handling and preparing foodstuffs. In the embodiment depicted in FIG. 1, the base 30 is formed from a series of vertical and horizontal framing members 32, 34 which are assembled together to form a supporting frame. The sides of the base 30 may be fitted with panels to create a cabinet enclosure, or the horizontal and vertical framing members 32, 34 may remain exposed. The base 30 may further include one or more shelves 36 to support components of the countertop 10, such as the refrigeration motor 28, or to provide convenient storage areas beneath the slab 12. In the embodiment shown, concrete slab 12 is supported on a top panel or shelf 38 at an upper end of the base 30. The lower edges of the slab 12, adjacent the top shelf 38 may be fitted with decorative trim 40. The base 30 may further include wheels or casters 42 provided at a lower end thereof to facilitate moving the countertop 10 as may be desired. Accordingly, the countertop 10 may be provided as a fixed installation or as a mobile or portable unit.

FIG. 2 is a cross-sectional view depicting another embodiment of a countertop 10 a according to the present invention, wherein the countertop 10 a is a portable unit that may be carried and placed upon an existing counter structure. Features of countertop 10 a, which are similar to features shown and described with respect to countertop 10, are similarly numbered. In this embodiment, the base 30 a includes a relatively smaller housing structure which encloses the refrigeration motor 28. The base 30 may be fitted with feet 44 at a lower portion thereof to facilitate locating the portable unit on the existing structure without scuffing or marring the structure.

With continued reference to FIG. 1, the countertop 10 may further include a control 50 in communication with the refrigeration motor 28 and operative to maintain the temperature of the work surface 14 of the concrete slab 12 within a desired temperature range. In the embodiment shown, the control 50 includes a display 52 for providing a visual indication of the temperature of the work surface 14, and a selector or input device 54, such as a dial, to permit users to set a desired temperature for the work surface 14. The control 50 will operate the refrigeration motor 28, (for example, by turning the motor on and off) to circulate refrigerant through the piping circuit 16 so that the desired temperature of the concrete slab 12 is attained and maintained. In one embodiment, the control 50 is operative to maintain the temperature of the concrete slab 12 within a range of approximately 40° F. to 80° F.

The concrete slab 12 of the countertop 10 is formed from a mixture of Portland cement, sand, water, and other additives such as structural fibers (e.g. glass fibers) and plasticizers to provide strength and durability to the slab. The concrete mixture may further include a liquid admixture that is formulated to stop moisture vapor migration, prevent alkali efflorescence attack and corrosion of embedded metal components. One such admixture is Moxie 1800 Super-Admix, available from Moxie International, Sacramento, Calif. An exemplary plastisizer that may be used is Melment® F10, available from SKW Chemicals, Inc., Marietta, Ga. Various pigments may also be added to the concrete mixture to color the concrete, as may be desired. Concrete pigments in various colors are available from Davis Colors Company, Beltsville, Md. In one embodiment, the slab is about 1½ to 2 inches thick. The slab 12 may be formed in any size and shape, as desired. For example, a slab which has a work surface within an envelope of not more than 24 inches wide and 24 inches deep, or 36 inches wide and 36 inches deep, may be desirable for a portable or relocateable countertop. Larger work surfaces 14, such as about 72 inches wide and about 36 inches deep, or even larger, may be suitable for countertops which are intended for more permanent installations, such as in commercial or residential kitchens. In addition, it will be recognized that the concrete slab 12 may be formed in custom shapes and various other configurations, as may be desired.

Referring now to FIGS. 3-5, one method of making a concrete countertop 10, 10 a according to the present invention will be described. To embed the piping circuit 16 within the concrete slab 12, a forming frame 60 having side walls 62, 64, 66, 68 arranged to define the periphery of the desired concrete slab 12 is partially filled with a first layer 70 of wet concrete. According to this method, the concrete slab 12 is formed “upside down” in the forming frame, such that the work surface 14 will be formed at a lower, first side 72 of the frame 60 and the bottom 74 of the concrete slab 12 will be formed at an open, upper, second side 76 of the frame 60. The first layer 70 is smoothed to evenly distribute the wet concrete within the form 60.

Before the first layer 70 cures, the piping circuit 16 is placed on the first layer 70 as depicted in FIG. 4. To ensure that the piping circuit 16 is located a desired distance from the work surface 14, the piping circuit 16 may be supported by tabs 78 or other structure extending outwardly from the piping circuit 16 to engage the top edges of the form 60. The piping circuit 16 is configured such that the first and second ends 20, 22 of the conduit 18 extend beyond the form 60, such as beyond the open, second end 76, so that the first and second ends 20, 22 of the conduit 18 will protrude from the formed concrete slab 12, as depicted in FIG. 5. While the first and second ends 20, 22 of the conduit 18 are shown and described herein to extend from the bottom 74 of the concrete slab 12, it will be recognized that the conduit 18 may alternatively extend from other portions of the concrete slab.

A second layer 80 of wet concrete is thereafter poured atop the first layer 70 and the piping circuit 16 so that the first and second layers 70, 80 of concrete coalesce to form a unitary concrete slab 12 with the piping circuit 16 embedded therein. The bottom surface 74 may then be smoothed with a trowel to create a substantially flat surface.

After the concrete slab 12 has sufficiently cured, the slab 12 is removed from the form 60 and the side defining the work surface 14 is ground and polished to a smooth, highly polished finish. In an exemplary embodiment, the work surface 14 is wet sanded with a 3500-grit diamond sanding pad to create this highly polished finish. In another embodiment, the surface roughness of the work surface 14 after finishing is between about two to four microinches. After the work surface 14 has been ground and polished, the work surface 14 is treated with a primer 82 and sealant 84, 86 to reduce or eliminate pores or small holes in the work surface 14, as depicted in FIGS. 1 and 2. In an exemplary embodiment, the work surface 14 is treated with two coats of a penetrating primer such as Primer 100, and two coats of a sealant such as Polyurethane 200 or Polyurethane 250 sealant, each available from Arizona Polymer Flooring, Inc. in Glendale, Ariz. In another embodiment, the total thickness of the sealant layer(s) 84, 86 applied to the work surface 14 is approximately 6 to 8 mils. Because the work surface 14 will come into direct contact with foodstuffs, the primer 82 and sealant 84, 86 must be safe for direct contact with foodstuffs. After the work surface 14 has been sealed, refrigerant may be placed in the piping circuit 16 and the piping circuit 16 coupled to a refrigeration motor 28 to form the countertop 10, 10 a as described above.

The following Examples illustrate exemplary concrete formulations useful for practicing the invention. Neither these examples, nor any of the foregoing disclosure, should be construed as limiting in any way the scope of the present invention unless otherwise indicated. All ingredients are given by weight.

EXAMPLE 1

No. Names of Ingredients (INCI) Weight 1 Coarse Sand 105.6 lb 2 Grey Cement 42.4 lb 3 Water 18.43 lb 4 Concrete Admixture (Moxie 1800) 253.0 g 5 Glass Fibers 87.0 g 6 Superplasticizer (Melment ® F10) 172.0 g

The ingredients listed above may be mixed together and poured into a form to make a concrete slab 14 with dimensions of approximately 36 inches wide, 36 inches deep, and 1½ to 2 inches thick.

EXAMPLE 2

No. Names of Ingredients (INCI) Weight 1 Coarse Sand 105.9 lb 2 Grey Cement 6.35 lb 3 White Cement 35.98 lb 4 Water 18.49 lb 5 Concrete Admixture (Moxie 1800) 254.0 g 6 Pigment (Davis Color #5447) 384.4 g 7 Glass Fibers 87.0 g 8 Superplasticizer (Melment ® F10) 173.0 g

The ingredients listed above may be mixed together and poured into a form to make a color tinted concrete slab 14 with dimensions of approximately 36 inches wide, 36 inches deep, and 1½ to 2 inches thick.

In some applications, it may be desirable to heat the work surface 14 as an alternative to, or in addition to, being able to chill the work surface 14. FIG. 2 depicts another embodiment of the present invention wherein one or more heating elements 90 are embedded in the concrete slab 12 in a manner similar to that described above with respect to the piping circuit 16. The heating elements 90 are in communication with the control 50, whereby the control 50 may operate the heating elements 90 to maintain the work surface at a desired elevated temperature.

While the temperature-controlled countertops of FIGS. 1-5 have been described above as comprising a piping circuit embedded in a concrete slab, the invention is not limited to concrete. In other embodiments, a piping circuit may be embedded in a moldable countertop material in a manner similar to that shown and described above. For example, a piping circuit according to the invention may be embedded into resin materials (such as Corian®), composite quartz countertop material, or other materials that can be formed or molded to surround the piping circuit.

While the present invention has been illustrated by the description of one or more embodiments thereof, and while the embodiments have been described in considerable detail, they are not intended to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and method and illustrative examples shown and described. 

1. A chilled countertop for preparing foodstuffs, comprising: a concrete slab defining a substantially planar concrete work surface; said work surface treated for direct contact with foodstuffs such that foodstuffs may be safely prepared directly thereon; a piping circuit embedded within said concrete slab; a refrigerant disposed within said piping circuit; and a refrigeration motor in fluid communication with said piping circuit and operative to circulate said refrigerant therethrough, said refrigeration motor comprising a compressor and a refrigerant expansion device; said work surface being cooled by circulation of said refrigerant in said piping circuit.
 2. The countertop of claim 1, wherein said work surface has a surface finish not more than about 2 microinches to about 4 microinches.
 3. The countertop of claim 1, wherein said work surface has a highly polished finish obtained by polishing with a tool of at least 3500 grit.
 4. The countertop of claim 1, further comprising: a penetrating primer applied to said work surface; and a sealant applied to said work surface, atop said primer.
 5. The countertop of claim 4, wherein said sealant has a layer thickness of approximately 6 mils to approximately 8 mils.
 6. The countertop of claim 1, further comprising a control in communication with said refrigeration motor and operative to maintain the temperature of said work surface of said concrete slab within a desired range.
 7. The countertop of claim 1, further comprising a base disposed beneath said concrete slab and supporting said concrete slab thereon.
 8. The countertop of claim 7, further comprising casters provided on said base to facilitate moving the countertop.
 9. The countertop of claim 7, wherein said work surface has a surface area within an envelope of not more than about 36 inches long and not more than about 36 inches wide for portability of the countertop.
 10. The countertop of claim 1, further comprising a plate coupled to said piping circuit and embedded within said concrete slab therewith to facilitate heat transfer between said piping circuit and said concrete slab.
 11. A method of making a countertop, comprising: embedding a piping circuit in a concrete slab; applying a primer to a work surface of the concrete slab, the primer being a type that is safe for direct contact with foodstuffs; and applying a sealant to the work surface of the concrete slab, the sealant being a type that is safe for direct contact with foodstuffs.
 12. The method of claim 11, further comprising: grinding and polishing the work surface to a smooth finish that has a surface roughness not more than about 2 microinches to about 4 microinches.
 13. The method of claim 11, wherein embedding the piping circuit in the concrete slab comprises: pouring a first layer of wet concrete into a form; placing the piping circuit on the first layer; pouring a second layer of wet concrete atop the first layer and the piping circuit prior to hardening of the first layer so the first and second layers coalesce to form a unitary concrete slab.
 14. The method of claim 11, further comprising: controlling the distance of the piping circuit beneath the work surface.
 15. The method of claim 11, further comprising: placing a refrigerant within the piping circuit; and coupling the piping circuit to a refrigeration motor including a compressor and a refrigerant expansion device for cooling the work surface.
 16. A temperature controlled countertop for preparing foodstuffs, comprising: a slab formed from moldable countertop material, said slab comprising a substantially planar work surface; said work surface suitable for direct contact with foodstuffs such that foodstuffs may be safely prepared directly thereon; a piping circuit embedded within said slab; a refrigerant disposed within said piping circuit; and a refrigeration motor in fluid communication with said piping circuit and operative to circulate said refrigerant therethrough, said refrigeration motor comprising a compressor and a refrigerant expansion device; said refrigerant cooling said work surface upon operation of said motor.
 17. The countertop of claim 16, further comprising a heating element embedded within said slab for heating said work surface.
 18. The countertop of claim 16 further comprising a control in communication with said refrigeration motor and said heating element, said control operative to maintain the temperature of said work surface of said concrete slab within a desired range. 